Synthetic aperture processing/imaging is a well-known enhancement technique used in wave propagation based target-detection systems such as radar, ground penetrating radar or underwater sonar systems. Each of these systems utilizes a wave equation to identify individual returns or reflections through time delay analysis. Synthetic aperture processing/imaging produces high resolution images and improves the signal-to-noise ratio for low level returns or reflections.
Not all target-detection applications can make use of the above-noted wave propagation based systems. For example, objects buried in the sea floor (e.g., mines, sunken vessels, etc.) are traditionally detected using electromagnetic sounding systems which generate images based on electrical conductivity anomalies. Since electromagnetic signals propagate underwater in accordance with a diffusion equation, recognition of individual returns or reflections is difficult. Therefore, use of synthetic aperture processing/imaging with such electromagnetic sounding systems is impossible. As a result, localization and characterization of a buried target can only be achieved by guessing at a model of the target, comparing the reflection with the guessed model, and making a better guess based on the comparison.